Search Results

You are looking at 1 - 8 of 8 items for :

  • Author or Editor: Sean Waugh x
  • Bulletin of the American Meteorological Society x
  • Refine by Access: All Content x
Clear All Modify Search
Aaron Kennedy
,
Aaron Scott
,
Nicole Loeb
,
Alec Sczepanski
,
Kaela Lucke
,
Jared Marquis
, and
Sean Waugh

Abstract

Harsh winters and hazards such as blizzards are synonymous with the northern Great Plains of the United States. Studying these events is difficult; the juxtaposition of cold temperatures and high winds makes microphysical observations of both blowing and falling snow challenging. Historically, these observations have been provided by costly hydrometeor imagers that have been deployed for field campaigns or at select observation sites. This has slowed the development and validation of microphysics parameterizations and remote sensing retrievals of various properties. If cheaper, more mobile instrumentation can be developed, this progress can be accelerated. Further, lowering price barriers can make deployment of instrumentation feasible for education and outreach purposes. The Blowing Snow Observations at the University of North Dakota: Education through Research (BLOWN-UNDER) Campaign took place during the winter of 2019/20 to investigate strategies for obtaining microphysical measurements in the harsh North Dakota winter. Student led, the project blended education, outreach, and scientific objectives. While a variety of in situ and remote sensing instruments were deployed for the campaign, the most novel aspect of the project was the development and deployment of OSCRE, the Open Snowflake Camera for Research and Education. Images from this instrument were combined with winter weather educational modules to describe properties of snow to the public, K–12 students, and members of indigenous communities through a tribal outreach program. Along with an educational deployment of a Doppler on Wheels mobile radar, nearly 1,000 individuals were reached during the project.

Full access
Robert J. Trapp
,
David J. Stensrud
,
Michael C. Coniglio
,
Russ S. Schumacher
,
Michael E. Baldwin
,
Sean Waugh
, and
Don T. Conlee

Abstract

The Mesoscale Predictability Experiment (MPEX) was a field campaign conducted 15 May through 15 June 2013 within the Great Plains region of the United States. One of the research foci of MPEX regarded the upscaling effects of deep convective storms on their environment, and how these feed back to the convective-scale dynamics and predictability. Balloon-borne GPS radiosondes, or “upsondes,” were used to sample such environmental feedbacks. Two of the upsonde teams employed dual-frequency sounding systems that allowed for upsonde observations at intervals as fast as 15 min. Because these dual-frequency systems also had the capacity for full mobility during sonde reception, highly adaptive and rapid storm-relative sampling of the convectively modified environment was possible. This article documents the mobile sounding capabilities and unique sampling strategies employed during MPEX.

Full access
Pedro L. Fernández-Cabán
,
A. Addison Alford
,
Martin J. Bell
,
Michael I. Biggerstaff
,
Gordon D. Carrie
,
Brian Hirth
,
Karen Kosiba
,
Brian M. Phillips
,
John L. Schroeder
,
Sean M. Waugh
,
Eric Williford
,
Joshua Wurman
, and
Forrest J. Masters

Abstract

While Hurricane Harvey will best be remembered for record rainfall that led to widespread flooding in southeastern Texas and western Louisiana, the storm also produced some of the most extreme wind speeds ever to be captured by an adaptive mesonet at landfall. This paper describes the unique tools and the strategy used by the Digital Hurricane Consortium (DHC), an ad hoc group of atmospheric scientists and wind engineers, to intercept and collect high-resolution measurements of Harvey’s inner core and eyewall as it passed over Aransas Bay into mainland Texas. The DHC successfully deployed more than 25 observational assets, leading to an unprecedented view of the boundary layer and winds aloft in the eyewall of a major hurricane at landfall. Analysis of anemometric measurements and mobile radar data during heavy convection shows the kinematic structure of the hurricane at landfall and the suspected influence of circulations aloft on surface winds and extreme surface gusts. Evidence of mesoscale vortices in the interior of the eyewall is also presented. Finally, the paper reports on an atmospheric sounding in the inner eyewall that produced an exceptionally large and potentially record value of precipitable water content for observed soundings in the continental United States.

Full access
Paul W. Staten
,
Kevin M. Grise
,
Sean M. Davis
,
Kristopher B. Karnauskas
,
Darryn W. Waugh
,
Amanda C. Maycock
,
Qiang Fu
,
Kerry Cook
,
Ori Adam
,
Isla R. Simpson
,
Robert J Allen
,
Karen Rosenlof
,
Gang Chen
,
Caroline C. Ummenhofer
,
Xiao-Wei Quan
,
James P. Kossin
,
Nicholas A. Davis
, and
Seok-Woo Son

Abstract

Over the past 15 years, numerous studies have suggested that the sinking branches of Earth’s Hadley circulation and the associated subtropical dry zones have shifted poleward over the late twentieth century and early twenty-first century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per decade, while estimates from global climate models show widening at the lower end of the observed range. In 2016, two working groups, the U.S. Climate Variability and Predictability (CLIVAR) working group on the Changing Width of the Tropical Belt and the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project, were formed to synthesize current understanding of the magnitude, causes, and impacts of the recent tropical widening evident in observations. These working groups concluded that the large rates of observed tropical widening noted by earlier studies resulted from their use of metrics that poorly capture changes in the Hadley circulation, or from the use of reanalyses that contained spurious trends. Accounting for these issues reduces the range of observed expansion rates to 0.25°–0.5° latitude decade‒1—within the range from model simulations. Models indicate that most of the recent Northern Hemisphere tropical widening is consistent with natural variability, whereas increasing greenhouse gases and decreasing stratospheric ozone likely played an important role in Southern Hemisphere widening. Whatever the cause or rate of expansion, understanding the regional impacts of tropical widening requires additional work, as different forcings can produce different regional patterns of widening.

Free access
Paul W. Staten
,
Kevin M. Grise
,
Sean M. Davis
,
Kristopher B. Karnauskas
,
Darryn W. Waugh
,
Amanda C. Maycock
,
Qiang Fu
,
Kerry Cook
,
Ori Adam
,
Isla R. Simpson
,
Robert J Allen
,
Karen Rosenlof
,
Gang Chen
,
Caroline C. Ummenhofer
,
Xiao-Wei Quan
,
James P. Kossin
,
Nicholas A. Davis
, and
Seok-Woo Son
Full access
Gijs de Boer
,
Constantin Diehl
,
Jamey Jacob
,
Adam Houston
,
Suzanne W. Smith
,
Phillip Chilson
,
David G. Schmale III
,
Janet Intrieri
,
James Pinto
,
Jack Elston
,
David Brus
,
Osku Kemppinen
,
Alex Clark
,
Dale Lawrence
,
Sean C. C. Bailey
,
Michael P. Sama
,
Amy Frazier
,
Christopher Crick
,
Victoria Natalie
,
Elizabeth Pillar-Little
,
Petra Klein
,
Sean Waugh
,
Julie K. Lundquist
,
Lindsay Barbieri
,
Stephan T. Kral
,
Anders A. Jensen
,
Cory Dixon
,
Steven Borenstein
,
Daniel Hesselius
,
Kathleen Human
,
Philip Hall
,
Brian Argrow
,
Troy Thornberry
,
Randy Wright
, and
Jason T. Kelly

ABSTRACT

Because unmanned aircraft systems (UAS) offer new perspectives on the atmosphere, their use in atmospheric science is expanding rapidly. In support of this growth, the International Society for Atmospheric Research Using Remotely-Piloted Aircraft (ISARRA) has been developed and has convened annual meetings and “flight weeks.” The 2018 flight week, dubbed the Lower Atmospheric Profiling Studies at Elevation–A Remotely-Piloted Aircraft Team Experiment (LAPSE-RATE), involved a 1-week deployment to Colorado’s San Luis Valley. Between 14 and 20 July 2018 over 100 students, scientists, engineers, pilots, and outreach coordinators conducted an intensive field operation using unmanned aircraft and ground-based assets to develop datasets, community, and capabilities. In addition to a coordinated “Community Day” which offered a chance for groups to share their aircraft and science with the San Luis Valley community, LAPSE-RATE participants conducted nearly 1,300 research flights totaling over 250 flight hours. The measurements collected have been used to advance capabilities (instrumentation, platforms, sampling techniques, and modeling tools), conduct a detailed system intercomparison study, develop new collaborations, and foster community support for the use of UAS in atmospheric science.

Free access
Karen A. Kosiba
,
Anthony W. Lyza
,
Robert J. Trapp
,
Erik N. Rasmussen
,
Matthew Parker
,
Michael I. Biggerstaff
,
Stephen W. Nesbitt
,
Christopher C. Weiss
,
Joshua Wurman
,
Kevin R. Knupp
,
Brice Coffer
,
Vanna C. Chmielewski
,
Daniel T. Dawson
,
Eric Bruning
,
Tyler M. Bell
,
Michael C. Coniglio
,
Todd A. Murphy
,
Michael French
,
Leanne Blind-Doskocil
,
Anthony E. Reinhart
,
Edward Wolff
,
Morgan E. Schneider
,
Miranda Silcott
,
Elizabeth Smith
,
Joshua Aikins
,
Melissa Wagner
,
Paul Robinson
,
James M. Wilczak
,
Trevor White
,
David Bodine
,
Matthew R. Kumjian
,
Sean M. Waugh
,
A. Addison Alford
,
Kim Elmore
,
Pavlos Kollias
, and
David D. Turner

Abstract

Quasi-linear convective systems (QLCSs) are responsible for approximately a quarter of all tornado events in the U.S., but no field campaigns have focused specifically on collecting data to understand QLCS tornadogenesis. The Propagation, Evolution, and Rotation in Linear System (PERiLS) project was the first observational study of tornadoes associated with QLCSs ever undertaken. Participants were drawn from more than 10 universities, laboratories, and institutes, with over 100 students participating in field activities. The PERiLS field phases spanned two years, late winters and early springs of 2022 and 2023, to increase the probability of intercepting significant tornadic QLCS events in a range of large-scale and local environments. The field phases of PERiLS collected data in nine tornadic and nontornadic QLCSs with unprecedented detail and diversity of measurements. The design and execution of the PERiLS field phase and preliminary data and ongoing analyses are shown.

Open access
Greg M. McFarquhar
,
Elizabeth Smith
,
Elizabeth A. Pillar-Little
,
Keith Brewster
,
Phillip B. Chilson
,
Temple R. Lee
,
Sean Waugh
,
Nusrat Yussouf
,
Xuguang Wang
,
Ming Xue
,
Gijs de Boer
,
Jeremy A. Gibbs
,
Chris Fiebrich
,
Bruce Baker
,
Jerry Brotzge
,
Frederick Carr
,
Hui Christophersen
,
Martin Fengler
,
Philip Hall
,
Terry Hock
,
Adam Houston
,
Robert Huck
,
Jamey Jacob
,
Robert Palmer
,
Patricia K. Quinn
,
Melissa Wagner
,
Yan (Rockee) Zhang
, and
Darren Hawk
Free access